
Nov. 14, 2007
11:16 a.m.
This is my first post, so here's a quick intro: I've recently joined the IronPython team at Microsoft, after about 6 years as a developer on the the .NET runtime (CLR). I'm currently trying to make IronPython match CPython's behavior regarding some % format string to a level of detail not documented by the spec. (http://docs.python.org/lib/typesseq-strings.html) While exploring to determine what CPython's behavior is, I'm hitting a SystemError in CPython. Given the following snippet: class c(long): def __oct__(self): return '100' x=c(5) oct(x) # expected to print 100 '%o' % x # expected to use print '5' It looks like in CPython, '%o' uses __int__ and so it should ignore __oct__ and print 5. However, I'm hitting an SystemError in CPython with this snippet: Python 2.5.1 (r251:54863, Apr 18 2007, 08:51:08) [MSC v.1310 32 bit (Intel)] onwin32 Type "help", "copyright", "credits" or "license" for more information. >>> class c(long): ... def __oct__(self): ... return '100' ... >>> x=c(5) >>> oct(x) # expected to print 100 '100' >>> '%o' % x # expected to use print '5' Traceback (most recent call last): File "<stdin>", line 1, in <module> SystemError: \loewis\25\python\Objects\stringobject.c:4236: bad argument to internal function Note that if c derives from 'int' instead of 'long', everything works as expected. 1. Can somebody confirm that '%o' should not use __oct__ and that is uses __int__ instead, and that the correct output from ('%o' % x) is indeed 5? 2. Should I file a bug for the SystemError exception? Thanks, Mike http://blogs.msdn.com/jmstall